Acid rain is caused by the presence of which gases in the atmosphere?
A. CO₂ and CO
B. SO₂ and NOₓ
C. H₂ and He
D. O₂ and N₂
Answer: Option B
Solution (By JKSSB Mock Tests)
Acid rain results from SO₂ and NOₓ (from burning fossil fuels) reacting with water vapor to form sulfuric and nitric acids. Normal rain is slightly acidic (pH ~5.6) due to CO₂ forming carbonic acid, but acid rain has pH < 5.6. Effects include corrosion of monuments (Taj Mahal), damage to aquatic life, and soil acidification. CO₂ causes global warming, not primarily acid rain.
Explanation:
Primary batteries are non-rechargeable; the chemical reaction that produces electricity cannot be reversed. The common dry cell (zinc-carbon battery) and alkaline batteries are primary cells. Lead-acid, Ni-Cd, and Li-ion are secondary (rechargeable) batteries where the reaction can be reversed by applying an external current.
Explanation:
Baking soda is sodium bicarbonate, with the chemical formula NaHCO₃. Sodium carbonate is washing soda (Na₂CO₃). Sodium hydroxide is caustic soda (NaOH), and calcium carbonate is limestone or marble (CaCO₃). Baking soda is widely used in baking as a leavening agent.
Explanation:
The ignition temperature (or kindling temperature) is the minimum temperature to which a fuel must be heated so that it catches fire and starts burning spontaneously. A lower ignition temperature means the fuel is more highly flammable and can ignite more easily at ambient conditions.
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